Abstract

In this work the concept of tracking-integrated concentrating photovoltaics is
studied and its capabilities are quantitatively analyzed. The design strategy
desists from ideal concentration performance to reduce the external mechanical
solar tracking effort in favor of a compact installation, possibly resulting in
lower overall cost. The proposed optical design is based on an extended
Simultaneous Multiple Surface (SMS) algorithm and uses two laterally moving
plano-convex lenses to achieve high concentration over a wide angular range of
±24°. It achieves 500× concentration, outperforming its
conventional concentrating photovoltaic counterparts on a polar aligned single
axis tracker.

Figures (8)

Inherent difference between a conventional (stationary) CPV module with its
acceptance angle α (a) and a tracking-integrated
CPV module with the aperture angle
αA of the optical system and
the acceptance angle α for a particular direction
(b).

Schematic drawing of a basic optical system consisting of two laterally
moving lenses and a receiver plane. The offset indicates the lateral shift
of the second lens for an off-axis incident ray set. All relevant parameters
describing the system are indicated.

Extended SMS2D design procedure to include motion by the alternate addition
of surface segments on the top and bottom surfaces of two plano-convex
lenses. The calculation starts through the center of the bottom surface
which determines the optical path length (a). It then proceeds through
mirroring (b) to the edges (c) of the lenses. Finally, all chains add up to
the final lenses that map the incident rays to the receiver point
R (d).

Exemplary single-frame excerpts from ray tracing animation of (a) line
concentration ( Media
1) and (b) point concentration (
Media
2) over the entire angular range. The
used designs are the two results obtained for θ
= 19° for line and point concentration.